Repairing electric motors is not just simply "fixing" a motor. You must perform a detailed forensics-like evaluation to first figure out what is even wrong with the unit. Just like forensics, evidence can be destroyed if you do not understand what sequence of events led to this point - and once the evidence is destoyed, you may never know what caused the failure.
Think of it this way...
We all have seen the television shows Crime Scene Investigators or CSI and their spin off series as well. Image the forensics personnel were walking into a crime scene with no understanding of what happened. Was there a burglary? a murder? a kidnapping? Where do they start? What approach do they take? As you can expect, they would take a different approach that depends on the unique situation.
I apologize for the gruesome analogy, but electric motor repair is very comparable to this. What happened to the motor before it came to the motor repair shop? Was it pulled as part of an outage? Was it pulled because it tripped the breaker? Was it pulled because it had high vibration? Whatever the case is, the approach the repair shop should take should be adjusted based on what has already occurred.
What questions should be asked?
There are a variety of questions that should be asked, however, they are somewhat dependent on your unique circumstances and the individual situation. However, the first question should simply be: "Why is this motor be sent out for repair?"
From there there should be a series of questions dependent on how you answer. If the motor is being pulled for high vibration, What was the vibration? How high was it? Do you have the vibration spectrum to share (FFT)? Can you send the historical trend data? What does the driven equipment's vibration look like?
If the motor is being pulled because it "Blew up", When did this happen? Did the motor show any signs of trouble before this? Did it happen at star-up or when the motor was already running? Do you track the current draw on the motor? Do you have any information on the current draw leading up to the failure? Do you track temperatures? What was the temperature trend?
All of this information needs to be used to look at the motor and attempt to solve the "root cause" of the failure. Without information, are you repairing what caused the issue or are you simply just repairing a result of the failure? The goal must be to get an understanding of what has taken place to then focus their inspection around what has led to that point.
So... is the shop you're using asking questions?
If your answer is yes, that is great. It tells us that you are using a repair shop that wants to solve the problem, not just fix the result. They care about making your equipment last longer and helping you have less headaches and 3am phone calls in the future.
If your answer is no, then you might want to consider evaluating why you are using them in the first place. Let's be clear, simply asking questions is not the only justification for using a repair shop or not. This is not questioning their experience, capabilities, or qualifications, which are all factors in considering which motor repair shop to use. If you are questioning this, it may be worth your time to take a look at our ebook, What to look for in an electric motor repair shop, which can help guide you on a variety of factors to consider.
HECO - All Systems Go
About the author:
Justin Hatfield is Vice President of Operations of HECO. He is responsible for Electric Motor & Drive Sales, Electric Motor & Generator Repairs, Spare Solutions, and Predictive Services. Justin was instrumental in developing HECO MAPPS(Motor And Powertrain Performance Systems)(Motor And Powertrain Performance Systems) which focuses on “why” you have a motor problem instead of simply “What” product or service should be recommended. HECO is an EASA Accredited Service Center.